Control apparatus



Sept. 6, 1938. E. c. RANEY 2,129,151

' CONTROL APPARATUS Filed Nov. 8, 1937 INVENTOR Patented Sept. 6, 1938UNITED STATES PATENT OFFICE CONTROL APPARATUS Estel C. Rancy, Columbus,Ohio, assignor to Ranco Incorporated, Columbus, Ohio, a corporation ofOhio This invention relates to a snap acting mechanism which may beutilized in control apparatus, or any other apparatus in which it may bedesirable to provide a positive snap movement in response to relativelyslight actuating movement.

, An object of the invention is to provide in a snap acting mechanism, apair of flipping members, each pivoted at one end and havingaspringconnecting the free ends, to bias the members to one side or the otherof a dead center position of each member, established relative to itsfulcrum and the spring, and providing for moving one of the members pastits dead center position to thereby move the second member past its deadcenter position with a snap action.

It is a further object of the invention to provide a snap actingmechanism, as set forth in the foregoing paragraph, in which the pivotsfor the flipping members are in different planes, thereby causing one ofthe members to be moved past its dead center in advance of the othermember to cause the latter member to be moved through its dead centerposition with a snap action.

It is a further object of the invention to provide in a snap actingmechanism, an actuating member and a snapping member, each pivoted atone end, and having a spring connecting the free end of the member forbiasing the members to one side or the other of a dead center positionof the membars, established relative to the fulcrum of the members andthe spring, in which provision is made for moving the free end of theactuating member from one side of its dead center position to the other,through a relatively fixed range of movement, to snap actuate the snapmember through its dead center position, and also for increasing thedistance of snap movement of the snap member in one direction.

Other and further objects of the invention will be apparent from thefollowing description, reference being bad to the accompanying drawingwherein a preferred form of embodiment of the present invention isclearly set forth.

In the drawing:

a Fig. l is a view, illustrating the position of the members of themechanism when the mechanism is at one of its limited positions;

Fig. 2 and Fig. 3 are views similar to Fig. 1, wherein the position ofthe members of the mech- 50 anism are shown, during one phase ofoperation of the device;

Fig. 5 and Fig. 6 are views similar to Fig. 1, showing the position ofthe members during a phase of operation of the mechanism in the re- 551verse direction to that shown in Figs. 2 and 3.

28 and 30.

The invention'is particularly adaptable to be used in thermostatic orpressure control devices and in the present disclosure, I have shown theinvention as it might be utilized in a. pressure control device 20. Thecontrol device 20, comprises a bell-crank lever 32 pivotally supportedat 34 on a part 2| of the frame of the control, the frame not beingshown except for the fragmentary part 21. An actuating rod 36 engagesthe lever in a detent 23, formed in a laterally extend- K ing part 21'of the lever 32, and is actuated in a vertical direction by any suitablemeans such as, for example, a diaphragm or bellows (not shown) inresponse to changes in pressures generated in response to actuation ofthe apparatus controlled by the device. It is to be understood, however,that the invention is in no way dependent upon the source of power usedfor actuating the rod 36.

A tension spring 38, partially shown in the drawings, is connected tothe arm 40 of the lever 32 through the eyelet 29 formed in the lever 4|]and its opposite end is connected to a suitable support (not shown),which may or may not be adjustable to vary the tension of the spring.The spring 38 is adapted to bias the lever 32 clockwise and place a loadupon the rod 36. The spring 38 controls the pressures at which themechanism will be operated.

In the operation of the control device, the rod 36 rotates the lever 32counterclockwise and the spring 38 acts to rotate the lever 32 clockwiseupon decrease in the pressure actuating the rod, thereby operating thesnap mechanism to be described presently.

Two pivot members 26, spaced apart, one being directly behind the otheras viewed in the drawing, are fixedly supported on the frame of thecontrol apparatus in any suitable manner, and each is provided with Vshaped fulcrums 28 and 30, to receive and pivot the ends of two flippersor members 22 and 24. The flippers are preferably U shaped, and disposedwith the closed end away from the pivots and the ends of the legsthereof being engaged in the fulcrums 28 and 30. A tension spring 25 isconnected at the closed portion of the U, of each of the flippers 22 and24, and is located betwen the pivot members 26 and the legs of theflippers 22 and 24. The spring 25 and its center of tension isrepresented by a broken line in Figures 2, 3, 4, 5 and 6. The tension ofthe spring 25, tending to draw the flippers together, maintains the endsof the flippers in the fulcrums The spring 25 also biases the snapflipper or member 22 against either the fixed member 46 or the endof thefinger 44 formed on the lever 22. The member 46 represents any means forcontrolling. the operation of apparathe, controlled by the device 20,such as, for example, a fuelvalve or any electric switch, which may beopened or closed by the flipper 22 striking or contacting the member 40.a

The pivots 2! and II lie in diflerent horizontal planes, as viewed inthe drawings, which causes oneortheotherottheflipperstopassthrough itsdead center position, i. e., the position of the flipper when theflipper and spring 2| lie in the same horizontal plane, before the otherflipper is moved 'to its dead center position, or in other words, wheneither one of the flippers is moved to its dead center position, theother or the flippers will remain biased to one side or the other of itidead center-position. This characteristic is illmtrated iii Figs. 2 and6, wherein the m a 1. Min its dead center position, while the flipper 22is biased to-the member 4|, and in Hg. 5, the flipper 22 is in its deadcenter position while flipper 24 is biased by lever 22,

The operation of the snap acting device is as follows:

When the control device 22 is at one limit of its function, as shown inFig. 1, the flippers 22 and 24 are biased against member 40 and stop 42respectively by the spring 2l As the rod 28 is raised, due to a functionof the apparatus controlled by the device 2|, the lever 32 is movedcounterclockwise. causing the stop 42 to move the flipper 24 upward, asshown in Pig. 2, until the flipper 24 has been moved past its deadcenter position, and instantaneously thereafter the spring 2| will snapthe flipper 24 upward against the stop 4|, as shown in Fig. 8, whichmovement carries the spring 2' above the pivot 22, thereby causing thespring 2| to snap the flipper 22 upward against the flnger 44 as shownin Fig. 4. It will be noted that when the flipper 24 has been moved toits dead center position, the spring 25 will continue to-exert asubstantial pressure on the flipper 22 against the member 40, since thepivot 28- is located in a plane above the pivot 20. when the pressuretending to move the rod 28 upwardly is reduced, the tension of thespring 22 causes the lever 22 to be moved clockwise. This swings theflnger 44 downward, moving the flipper 22 to its dead center position,as shown in Fig. 5, and simultaneously, stop 40 moves the flipper 24downwardly toward its dead center position. Further movement of thelever 32 by thespring 22 moves the flipper 22 past its dead centerposition, causing the spring 25 to instantaneously snap the flipper 22against the member 48. Themovementoi the flipper 22 to the member 48together with-the movement of stop 4|, carries the spring 2! below thepivot and thereby causes the flipper 24 to be snapped through its deadcenter position to the stop member 42.

Particular attention is directed to the operation and arrangement of theactuating lever 22 and its members 4|, 42 and 44. Each of the stops 4|,42 and the flnger 44 are movable to actuate the flippers and to alsolimit the movement there- 01'. By combining these functions of themembers, it is possible to secure a snap mechanism having a relativelysubstantial snap movement in response to a relatively short movement ofthe actuating element, as i'orexample, in the present disclosure, theflnger member 44, .being lo-- cated on the end of the lever 22, is moveda relatively greater distance from the end of the flipper 22 upon slightupward movement of the actuating rod 26, so that when the flipper 22 issnapped asainst the flnger 44, the free end oi the flipper will be moveda substantial distance from the member 48, with a snap movement. As

' the lever 22 is moved clockwise, a relative short downward movement oithe rod it permits the member 44 to move the flipper 22to its deadcenter position from 'which position it is snapped to the member 42. Thestop 4i, moving simultaneously with the flnger 44, moves the flipper 24nearer its dead center so that when the flipper 22 is mapped against thestop 48, the flipper 24 will have been moved'to a position that willallow the spring 25, to snap it against the stop member 42. Thus. bysimultaneously moving both flippers toward, andthrough their dead centerpositionsrespectively, the movement oithe actuating rod 28 may beeflectively multiplied to produce a positive snap action of theflippers.

The wide opening of the flipper 22 is especially desirable ii the deviceis utilized as an electric switch, in which the flipper 22 carries acontact for making the electric circuit at 48. The wide brake or thecontact permits a high current rat-- ing for the switch due to theinstantaneous and wide movement of the flipper 22 away from 48.

Although one form of the invention is disclosed, it is to be understoodthat changes may be made in the form and use 01' the invention and yetfall within the scope is set forth in the claims.

1. In a snap acting device, a pair or members each pivoted at one endthereof; resilient means acting on the free ends of the members to biasthe members to one side or the other of a dead center position withrespect to the member, its pivot and the line of iorce of the resilientmeans; and actuating means enga ing each of said members adjacent thefree ends thereof for moving the members toward their dead centerposition, said actuating means being adapted to move one oi the memberspast its dead center position to cause the last mentioned member to snapthe other member past its dead center position.

2. In a snap acting device, a pair oi members each pivoted at one" endthereof; resilient means acting on the free ends 0'! the members to biasthe members to one side or the other of a dead center position withrespect to the member, its pivot and the line of force 01' the resilientmeans; and actuating means engaging the members adjacent their free endsfor. moving one of the members past its dead center position andsimultaneously moving the other of the members tooi my invention which Iward its dead center position.

in one direction to cause the members to be moved past their dead centerpositions and for engaging only one of the members to move the same pastits dead center position in the opposite direction when the actuatingmeans is actuated in the reverse direction.

4. In a snap acting device, a pair of flippers; each of the flippersbeing pivoted at one end thereof; resilient means connecting theflippers adjacent the free ends thereof, the flippers each having a deadcenter position with respect to its pivot and the spring, said resilientmeans normally acting to bias the flippers to one side or the other oftheir dead center position; actuating means for engaging one of theflippers adjacent its free end to move the flipper past its dead centerposition and for engaging the other of the said flippers adjacent itsfree end for moving the last mentioned flipper toward its dead centerposition during movement of the actuating means in one direction, andmeans for moving the actuating means.

5. In a snap acting device, a pair of flippers; each of the flippersbeing pivoted at one end thereof; resilient means connecting theflippers adjacent the free ends thereof, the flippers each having a deadcenter position with respect to its pivot and the spring, said resilientmeans normally acting to bias the flippers to one side or the other oftheir dead center positions; movable means for engaging each of theflippers adjacent the free ends thereof, when moved in one direction, tomove one of the flippers toward its dead center position whilesimultaneously moving the other of the flippers past its dead centerposition, said movable means, when moved in the opposite directionengaging one of the elements to move the same past its dead centerposition, and means for moving the movable means.

6. In a snap acting device, a pair of members each pivoted at one endthereof, a spring connecting the free ends of the members to normallybias the members in one direction, each of the members having a deadcenter position relative to its pivot and the spring; an actuatingelement for moving one of the members past its dead center position; alost motion connection between the actuating element and the member; anelement for, engaging the other of the members to move the member pastits dead center position while the actuating element moves the firstelement towards its dead center position; and means for moving the saidelements simultaneously.

7. In a snap action device, an actuating member and a snap member, eachpivoted atone end thereof; a spring connecting the members,- each memberhaving a dead center position relative to its pivot and the spring; anactuating element, a lost motion connection between the element and theactuating member, the element being operative to move the actuatingmember past itsv dead center position and thereby snap actuate the snapmember, a. movable element for moving the snap member past its deadcenter position when the element is moved in one direction; means foractuating said elements simultaneously, and for moving the actuatingmember past its dead center before the snap member ismoved to its deadcenter position, to cause the actuating member and spring to move thesnap member past its dead center position with a snap action.

8. In a snap acting device, a pair of members each pivoted at one end; aresilient element connecting the free ends of the members for biasingthe members in either of two positions; means for simultaneouslyengaging each of the members adjacent the free ends thereof for movingthe members from one of said positions to cause the resilient element tobias the members to the other of the said positions with a snapmovement; and means for moving the last mentioned means.

9. In a snap acting device, a pair of members each pivoted at one end, aresilient element connecting the free ends for biasing the members ineither of two limited positions, each of the members having a deadcenter position relative to its pivot and the resilient element, saidpivots lying in different planes; movable means for engaging the freeend of one of the members to move it from one of said limited positionsthrough its dead center and for engaging the free end of the othermember to move the last mentioned member toward its dead centerposition; and means for moving the last named means.

1 0. In a snap acting device, a pair of members each pivoted at one endthereof; resilient means acting on the free ends of the members to biasthe members to one side or the other of a dead center position withrespect to the member, its pivot and the spring; stops for limitingmovement of the free ends of the members about thepivots; and means formoving one of the stops to move one of the members past its dead centerposition to cause snap movement of the other of the members, and forsimultaneously moving one of the stops for the latter member.

11. In a snap acting device, a pair of members each pivoted at one endthereof; resilient means acting on the free ends of the members to biasthe members to one side or the other of a dead center position withrespect to the member, its pivot and the spring; stops for limitingmovement of the free ends of the members about the pivots; means formoving the stops of one of the members to move the member past its deadcenter position, and snap actuate the other of the members; and meansfor moving one of the stops for the latter element prior to the saidsnap movement thereof.

12. In a snap acting device, a pair of members each pivoted at one endthereof, resilient means acting on the free ends of the members to biasthe members to one side or the other of a dead center position withrespect to the member, itsvpivot and the spring; stops for limitingmovement'of the free ends of the members about the pivots; means formoving the stops of one of the members to move the member past its deadcenter position, and snap actuate the other of the members; and meansfor moving one of the stops for the latter member away from said memberprior to the snap movement thereof by the

